Sling attachment device



FIG. 1 is a perspective view thereof;

FIG. 2 is a top view thereof, the bottom view being a mirror image thereof;

FIG. 3 is a front view thereof, the back view being a mirror image thereof;

FIG. 4 is a left side view thereof; and,

FIG. 5 is a right side view thereof.

The broken line showing of aspects of the sling attachment device forms no part of the claimed design. 

CLAIM The ornamental design for a sling attachment device, as shown and described. 